The Effects of Depression on the Brain

Written by Stephanie Faris
| Published on March 28, 2012Medically Reviewed by George Krucik, MD

Researchers have found a link between depression and the size of the sufferer’s brain. Find out what parts of the brain are affected and what treatments exist.

Those suffering from depression typically
have more immediate concerns than the long-term effects of depression on the
body. However, researchers have found a link between depression and the size of
the sufferer’s brain. A certain section of the brain is believed to shrink in
victims suffering from the disease.

Glucocorticoids and the
Damage They Cause

High levels of depression have been
associated with an increased level of cortisol (a steroid hormone) in about
half of all cases. Excess cortisol has been linked to damage to the hippocampal
neurons, an area of the brain important to memories. However, recent studies show that this excess may
also have an effect on brain size.

One study tested
patients with varying levels of depression and compared them to patients with
no instances of depression. The study found a 19 percent reduction in the size
of the left hippocampus in patients with recurring severe depression. There was
no difference in other sections of the brain.

Another study compared major depressive
patients in remission to those who had never suffered from the condition and
found reduction in size of both the left and right hippocampal regions. The
study noted that reduction in size of the hippocampus corresponded to the
number of days a subject spent depressed, concluding that depression is
associated with reduction in size of the hippocampus. The study also concluded,
as did the previous study mentioned, that this reduction could lead to further
depressive episodes

Theories About the
Reduction

While scientists have not yet pinned down
the exact cause of the reduction, high levels of glucocorticoids may be the
cause of the damage. In fact, researchers theorize that over time, repeated
episodes of depression may cause the hippocampal section of the brain to further
atrophy, leading to increased episodes of depression.

Another theory is that a reduction in
neurotrophins could cause the hippocampal size reduction. Or, the hippocampus
may be smaller in severe depression patients from birth, possibly leading to
the condition later in life. However, further studies should be made into the
relationship between glucocorticoids and hippocampal shrinkage.

Hippocampal Atrophy
Effects on Depression Patients

The hippocampus is the section of the
brain associated with memory recall and emotions. The shrinkage problem appears
to be most marked in cases of depression that last for multiple days and recur
frequently. This shrinkage is generally minor and is usually connected only
with an increased risk of further depressive episodes. However, the brain size
showed noticeable changes in the hippocampal region in severe cases of
depression that last for years—especially in those whose depression started in
childhood.

In addition to a predicted increase in
incidents of depression, this reduction in size of the hippocampus is linked to
possible memory loss. Researchers reference Alzheimer’s patients, who have also
been found to have hippocampal shrinkage. While memory loss is not as severe in
depression patients, researchers have found that test patients have a
noticeable loss in verbal memory—meaning they have an inability to remember
words. Visual memory has not shown impairment in studies of depressive
patients.

Treatment for Depression
and Brain Shrinkage

Depression treatment like Prozac can help
combat this reduction by regulating the serotonin. More studies need to be done
on the effects of antidepressants on glucocorticoids, but taking these
medications could help prevent permanent damage.

A study by a
group of researchers at the National Institute of Mental Health in Maryland
found an increase in memory retention after just seven months of treatment with
the antidepressants Prozac or Effexor. Even better news is that these
treatments have shown to reverse shrinkage that has already occurred in study
patients.

This research
emphasizes the importance of treatment for those patients suffering from
depression. Not only does treatment help keep symptoms at bay and improve
quality of life, it may be the key to preventing and even reversing permanent
brain size change in patients with severe recurring depression.

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